1. Field of the Invention
The invention in general relates to semiconductors, and more particularly to a silicon carbide static induction transistor capable of high temperature, high frequency, high power operation.
2. Description of Related Art
A typical SIT (static induction transistor) is a vertical structure semiconductor device wherein electrical current flows from a plurality of source regions to a drain region, on opposite sides of a substrate member. Current flowing from source to drain is controlled by a potential barrier induced by gate regions positioned between the sources. The region between the source and gates is known as the channel region, while the region between the bottom of the channel region and drain is known as the drift region.
One popular type of SIT is the Schottky gate SIT wherein the gates are metal areas applied directly to the semiconductor body in an alternate arrangement with the sources. Problems with such Schottky gate SITs include inconsistent gate fabrication, reliability, and general difficulties in the manufacturing process.
Another type of popular SIT is the ion implanted gate SIT. Problems arising in the manufacturing process for these SITs include imprecise spacing of the gate to source, erratic breakdown of the gate to source and the requirement of multiple masks. These masks must be 100% precisely aligned, which is not always the case, particularly when hundreds of SITs are simultaneously fabricated on the same semiconductor wafer.
It is an object of the present invention to provide a fabrication process for a SIT which eliminates the problems associated with prior art SITs.